I'm interested - I assumed (!) that flight plan procedures were international. I guess this explains the difficulty in finding an answer that should be a fairly simple question.

Chevvron - this is for both VFR and IFR flights? All countries in Europe?

No, as per the quote, I was referring to IFR flight plans only and it's valid for all countries whose IFR plans are sent via IFPS.
A someone else pointed out, you found a list of requirements for the USA where their rules have to take into account their 'blanket' Class E airspace and the fact that many airfields in the USA aren't connected to AFTN and instead have their own system of forwarding plans from the closest ATCC or FSS (Flight Service Station).

That was part of the training for my instrument ticket, fly an instrument approach into a non towered field then call the FSS and file a departure IFR plan over the phone. IIRC I had 30 minutes from hang up to get in the air and make contact.

Hm. Whilst the red herrings are of interest, my question was about VFR flight plans, and when you can/should depart with reference to the filed time..

CAP 694, the UK Flight Planning Guide answers all your questions. Download as a PDF and find instances of TIME and Delay and all will be revealed.
Generally 60 mins notice is required before startup, exceptionally 30 mins may be possible. Window is up to 60 mins late for uncontrolled flights - otherwise 30 - however a delay mesaege may be sent to avoid the need for resubmission of plan.

I've already looked at that, but all I've found is Para 10, chapter 6, page 6. Which explains what to do for IFR flights. I haven't found anything there about VFR flights.

Not for that it's not there, something of an HD document, but I certainly couldn't find it - nor anything that mentions this subject at all apart from the US based document posted earlier.

So, the question remains, can I leave early on a VFR flight plan, and how early?!

Funny - should be a simple question easily answered, but clearly isn't.

In NL it's plus or minus 30 minutes of EOBT for VFR. (ref NL AIP, ENR 1.10) (*)

Trying to leave more than 30 minutes early requires a cancellation and refile, which is easiest done if you call the FIS directly. Leaving late requires sending a Delay message.

(If the delay is due to weather then I typically call up Rotterdam Delivery on their frequency and ask them to push back the plan a bit. They are normally kind enough to keep pushing it back if the weather conditions don't improve as quickly as planned, until I contact them to ask for startup, or cancel the flight altogether.)

Formally a flight plan needs to be submitted an hour before EOBT, but in practice it can be much less. VFR flight plans submitted electronically (homebriefing.nl, SkyDemon, whatever) still need a human in the FIS office pushing the button before it's distributed. They tend not to be amused if you make a habit out of submitting them with very short notice when there's no need. So if you do need to file at short notice, best to call them and coordinate with them. Once the person at the other end of the phone line has accepted your plan and submitted it for distribution, it will be available at the TWR virtually instantaneously.

We fly VFR from a controlled field (EHRD) in the Netherlands, which requires a formal flight plan for every flight. All the "based" pilots tend to get very proficient at "working the system" very quickly. There have been several occasions where I called Delivery for startup and found out there was something wrong with the plan. Grab the cellphone, call the FIO, sort out the problem and have them submit a new plan. Switch on the avionics again and ask for startup again. Easy.

(Edited)
(*) The plus 30 minutes window is pretty well established, but I can't find any reference in the AIP for the minus 30 minutes window. Maybe it's in EASA-SERA?

Next time try calling the ARO office, instead of the ground controller.

Okay, so still no reference in any official document for leaving early on a VFR flight plan?!

As I said before, most places in the UK a DEP is sent so if the plan is in the system, it doesn't matter.

ICAO PANS-ATM says

4.4.2.1.2 In the event of a delay of 30 minutes in excess of the estimated off-block time for a controlled flight or a delay of one hour for an uncontrolled flight for which a flight plan has been submitted, the flight plan should be amended or a new flight plan submitted and the old flight plan cancelled, whichever is applicable.

It offers no guidance on departing early, though it does say elsewhere (11.4.2.2.2.5) that:

transmission of the FPL message may be withheld until one hour before the estimated off-block time, provided that this will permit each ATS unit concerned to receive the information at least 30 minutes before the time at which the aircraft is estimated to enter its area of responsibility.

This would imply that departing more than 30 mins early might break the system.

The IFPS User's Manual, which applies to IFR FPLs in Europe (and hence does not answer your question), says:

Any changes of more than 15 minutes to the EOBT of a filed flight plan shall be communicated to the IFPS. The IFPS shall not accept negative delays: should the EOBT of a flight need to be changed to an earlier time that flight must be cancelled and re-filed with the earlier EOBT.

Note Although it is not a requirement to update the EOBT of a non-ATFM-regulated flight where the change is not more than 15 minutes, it is recommended to make such an update to the flight plan held by the IFPS.

The Belgian AIP has info about delaying but is silent as far as I can tell bringing forward flight plans. It does have info specific to VFR flight plans. ENR 1.10 seems to be the place to look. In this instance I imagine the VFR flight plan was filed because of a requirement (as stated in AIP) to do so because ATC services are required ( ie departing from a controlled airfield) and this is why it is less flexible than a VFR flight plan filed solely for SAR purposes.

https://www.belgocontrol.be/html/bel...dex-en-GB.html

If referring to my experience, I filed a flight plan because I was flying to Switzerland. Non-international VFR flights into/out of Brussels Charleroi do not require flight plans.

You could be restricted since you were flying out of EU? I do not know how EU-Swiss regulations are, but between Norway and EU (Sweden) there are certain requirements.

When we arrive in Norway we are not allowed to leave the aircraft before the arrival time in the flight plan unless we call Norwegian customs and get approval. This is because customs want to have the possibility to do random inspections and they do their planning according to the times filed in the flightplan. Usually I solve this by trying to arrive on time, or a tiny bit late, good training in flightplanning.

For departures from Norway the customs needs to be notified about the departure time at least 60 minutes before departure if we are traveling outside Norway (when departing from a airport with a manned customs office). I guess this is because they want to be able to do spot check of departing planes as well (i.e. large amounts of cash requires reporting to authorities before export).

It could be similar restrictions from the local customs office in Brussels that was the reason you were not allowed to leave early?

I don't think so. Both departure and arrival airports are full international, no prior notice or permission required.

Indeed, that's not what the guy said on the radio.

He simply said that "on a VFR flight plan you can only depart during the period from departure time filed up to +30 minutes". I'm absolutely certain he's wrong, but cannot find any official document (anywhere in the world) that explains the full rules (including leaving early).

My departure airport is also fully international, ENGM - Gardermoen which is the largest airport in Norway, but I agree that the reply you got suggests it is (or the controller think it is) restricted by VFR rules.

In the VFR guide to Norway it is clearly stated:

"If you like to bring your EOBT forward or
delay your flightplan, this is not a
problem.
Notify ATC or call AIS (tel. (+47) 64 81
90 00 (H24)) if you change the EOBT
more than 30 mins. either way. "

Generally Norway follows EASA rules and we have implemented most of the SERA regulations, however SERA allows for national differences in some cases.

However when checking the British VFR Guide it only covers delays not early departures.

Okay, so Norway is first through the door with an official document covering an early VFR departure. No others?

Is this weird, or am I the only one interested by the apparent absence of regulation?

Sam
The absence of any written information maybe a blessing in disguise as one could blag it

Steve

If an aircraft departs our airfield early on a VFR flight plan we just send a DEP message in the usual way. Happens all the time but usually minutes,not hours early....Never been a problem.

If an aircraft departed an hour early we would do the same.

UK airfield,A/G,outside controlled airspace.

That's my experience too.